It is well known that some microorganisms are capable of producing metabolites showing interesting biological activities. Such compounds are of potential interest for use in various fields, such as medicine, agriculture, food industry etc.
In the agricultural field biocidal microbial metabolites are considered to be highly interesting alternatives to the synthetic and, from an environmental point of view, generally undesirable compounds normally used for controlling diseases and pests in valuable crops. Accordingly, a fair amount of research has been devoted to the identification and development of such metabolites, which research to date, however, has resulted in only few useful biological (i.e. metabolite based) biocides as compared to the vast number of synthetical biocides presently used. It is consequently desirable to find further microbial metabolites useful as biocidal agents.
Hydroxyalkanoic acids are commonly occurring metabolites in various organisms. Polymerics forms of these, and especially poly .beta.-hydroxybutyric acids, typically composed of several hundreds of units, occur in many bacteria as storage material, with the same function as starch and glycogen in higher organisms (Steinbuchel (1991)). Cyclic oligomers, being somewhat related to the compounds of the present invention, have also been described (Seebach et al. (1988)), but apparently no biological activity has been associated with these compounds.
The genus Penicillium is known to be an efficient producer of secondary metabolites having a diversity of structural features. One group of secondary metabolites encountered in said genus is macrocyclic lactones or the macrolides. An example from this group is the 16-membered dilactone vermiculin (P. vermiculatum) which exhibits antimicrobial effects (Fuska et al. (1972)), (Sedmera et al. (1973)), (Boeckman et al (1974)).
JP-A-3-262489 discloses a metabolite termed NG-012 produced by and isolated from a strain of Penicillium verruculosum F-4542. NG-012 was reported as a nerve growth factor potentiator, and no further activity of this compound was described or indicated. No mention or indication of the structure of NG-012 was given in the above cited Japanese application. The structure of this compound was reported only after the filing date of the present application, cf. the disclosure of Mayumi Ito et al., October 1992.